The present invention relates to an improved screening screen assembly for a vibratory screening machine.
Undulating screening screen subassemblies adhesively bonded to apertured plates are shown in U.S. Pat. Nos. 5,417,859, 5,417,853 and 5,417,793. The plates such as shown in these patents have apertures bounded by relatively narrow plate members or strips, each of which provides a very limited area of adhesive securement or bonding to the undersides of troughs of undulating screens. While the foregoing adhesive securement to relatively narrow frame members is satisfactory for most environments, if it is utilized in corrosive environments, the adhesive bond between the undersides of the troughs and the narrow strips of the plate could be eroded because of the relatively small areas of adhesive contact therebetween. In the past there have also been in use plates or frames which comprised elongated relatively wide strips between the side edges of the plates or frames, with elongated openings or apertures between the strips, and such elongated openings extended substantially the entire length between the side edges. However, in screening screen assemblies of this type, there was no support for the elongated strips between their ends because of the fact that the openings between the strips extended substantially the entire distance between the side edges. Thus the elongated strips were essentially adhesively bonded to each other by the undulating screen, and when the screening screen assemblies were handled, the elongated plate strips could flex relative to each other with the attendant possibility that the bond between the undulating screen subassembly and the elongated strips could be broken.